The cause of death remained a puzzle Tuesday. The medical examiner conducted an autopsy and found no sign of trauma, saying additional tests are necessary. Results could take weeks.

Dr. Steve Karges, a St. Petersburg pediatrician, said possible causes are a severe seizure or arrhythmia, a disruption in rhythmic beating of the heart.

"I don't think sheer terror would do it," said Karges, who has been on the $100-million space-flight simulator. "Fear doesn't kill people."

The ride spins passengers, seated four to a pod, at high speed around a centrifuge about 50 feet in diameter. With visual effects displayed on monitors, the rocket blasts off with a loud noise and smoke. The G-force can lightly pull back the skin back on one's face.

The ride was built by Entertainment Technology Corp. of Southampton, Pa. Officials there declined comment. The company filed a $15-million lawsuit against Disney in 2003, alleging it was not paid in full and not allowed to perform safety tests. The case is still in litigation.

Daudi Bamuwamye came to Disney with his mother, 8-year-old sister, Ruth, and father, Moses, a United Nations financial official. The family lives in Sellersville, Pa., about an hour north of Philadelphia.

Before getting dressed for Epcot, family members had breakfast in their hotel room, according to a sheriff's report. Daudi had four grape Kool Aids, an oatmeal bar and several slices of white bread with jelly.

They arrived at noon and were in line at Mission: Space at 2:30 p.m. After 10 minutes, Daudi said he had to go the restroom. They returned to the ride and entered at 3:14 p.m.

Along the way to the capsule, the family would have been bombarded with warning signs about the ride's intensity; Disney said it has at least a dozen at the attraction. Audio and video warnings are also played.

One sign posted last year read: "For safety you should be in good health, and free from high blood pressure, heart, back or neck problems, motion sickness or other conditions that can be aggravated by this adventure."

As the ship prepared for blast-off, Daudi sat in the commander's chair, between his mother and sister.

Four minutes later, his mom rushed out with him in her arms. A Disney worker helped her lay the child on a bench and they performed CPR, the sheriff's report said, as rescuers were called. When paramedics arrived, they took over CPR then rushed Daudi to nearby Celebration Hospital.

He was declared dead at 4:52 p.m.

The family released a statement through the medical examiner, thanking people for their concern. "We would ask that you continue to respect our privacy as we struggle with this heartbreaking and devastating loss."